<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Test03</title>
</head>
<body>
    <script type="text/javascript">
        var a = "1";
        var b = 2;
        var c = null;
        var d = true;
        var e ;         // 当声明的变量未初始化时，该变量的默认值是 undefined。
        var f = [1,2,3,"456"];
        var g = 1;
        console.log(typeof a);
        console.log(typeof b);
        console.log(typeof c);
        console.log(typeof d);
        console.log(typeof e);
        console.log(typeof f);
        console.log(typeof g);

    </script>
</body>
</html>